Pbeparation of acetoacetanilid



30 ture. v formed, probably due-to the presence of traces of PatentedDec. 4, 1934 PATENT OFFICE).

Q PREPARATION OF ACETOACET ANILID George H. Law, South Charleston, W.Va., as-

signor to Carbide and Carbon Chemicals (Lorporation, a corporation ofNew York No Drawing. Application December 2, 1933,

Serial No. 700,729 g I 10 Claims. (01. 260-124) The invention relates toan improved process for preparing acetoacetanilid. I

Acetoacetanilid, indicated by the formula CHs-CO-CHg-CO-NH-CeHs, is acrystalline substance having a melting point of about 84 C. Amongvarious chemical uses to which it is adapted, it serves as anintermediate for the production of a yellow pigment, known as Hansayellow. The material hasheretofore been made by reacting aniline withesters 'of aceto-acetic acid.

It is an object of my invention to provide a new process for makingacetoacetanilid, in a manner more efiicientand economically feasiblethan any heretofore known.

I have found that diketene, commonly designated by the structuralformula will react with aniline under properly controlled conditions toprovide a very good yield of acetoacetanilid. An inert solvent,preferably one in 5 which acetoacetanilid is quite soluble when hot,

but from which it can readily be recovered on cooling, is used inconducting the reaction, whereby the main portion of the product can becrystallized out in pure state from the reaction mix- A small amount ofacetanilid is also acetic anhydride in the diketene. This may be removedfrom the acetoacetanilid by selectively treating the residue or thesolution with an extractant for acetoacetanilid.

v aluminum kettle equipped with a brine cooled refiux condenser and adropping funnel. This mixture was agitated with a current of dry naturalgas, and 4000 grams of diketene of 93% purity were slowly added throughthe dropping funnel. While adding the diketene the kettle was cooled ina water bath, and the rate of addition was controlled so as to maintaina temperature of C. to 70 C. in the reaction mixture. On completion ofthe reaction the hot make was transferred to an aluminum crystallizingvessel and cooled to 20 C. This caused crystallization of a largeportion of the acetoacetanilid, which was filtered off. The motherliquor was then cooled to 5 0., and a second group of crystals filteredoff. The remaining liquor and the wa h uble material were thenevaporated toa volume, of approximately 3 liters, and cooled to 0 C. toobtain a third group of crystals. Thislatter material was found to be amixture of both acetoacetanilid and acetanilid. It was extracted with ay5% solution of aqueous sodium hydroxide, which was fil- M tered andacidified to precipitateacetoacetanilid. This caustic soluble materialwas then recrystallized with a decolorizingcarbontreatment to yield pureacetoacetanilid, and the caustic insolupon like treatment yielded pureacetanilid. l

Data obtained from the above example'are as follows:

Diketene efiiciency (based on acetoacetanilid) 86.5% Diketene efficiency(based on acetanilid) 0.6%

cipitate the acetoacetanilid as an ,oil.

The first crystallization step removes the greater portion of theacetoacetanilid from the reaction solution, and as a modification of theabove procedure, caustic extraction of the solution may be performedafter the first crop of crystals is filtered oil. This would avoid theprogressive concentration of the mother liquor, and may be desirable asa means of accelerating the process. Aluminum equipment is preferablyused up to the point of caustic extraction, since iron rapidlypolymerizes diketene and also imparts a color to acetoacetanilid. Thisproduct is also colored by contact with copper or copper alloys, andrecrystallization is necessary to remove traces of dissolved copper, ifthe caustic extraction is performed in contact with this metal.

comprises treating aniline with diketene in the presence of a solventfrom which 'ac'etoacetanilidwill crystallize out on cooling. ,v I

3. Process for making" acetoacetanilid which comprises treating anilinewith dik'etenein the presence of a medium solvent to both aniline andacetoacetanilid while hot, and crystallizing out acetoacetanilid bycooling the reaction mixture.-

4. Process for making acetoacetanilid which comprises dissolving anilinein a solvent which will also dissolve acetoacetanilid while hot, addingdiketene slowly to'the solution, and crystalliz'i'ng-out acetoacetanilidfrom-the reaction mixtureby cooling. v

5.- Process for making 'acetoacetanilid which comprises dissolvinganiline in a solvent which will also dissolve acetoacetanilid while hot,adding 'dike'tene' 'slowly' to the solution; crystallizing out a majorportion of the'acetoacetanilid from the reaction mixture bycodling; andsubsequently removing the remainder of the acetoacetanilid by extractionwith a caustic solution. Y

' 6; Process for making 'acetoacetanil-id which comprises treatinganiline with diketene inthe presence of a toluene solvent, andcrystallizing out acetoacetanili'd' from the "reaction mixture-by;cooling.

'1; A rocess 'formaking acetoacetanilid which comprises treatinganilinewith 'diketene' the presence of a toluene solvent, crystallizingout a major portion of the acetoacetanilid by progressive cooling of thereaction mixture, and subsequently removing the remainder of theacetoacetanilid by extraction with an aqueous caustic solution. l

8. Process for making acetoacetanilid which comprises dissolving anilinein toluene, slowly adding diketene to the solution while maintaining thereaction mixture to a temperature of about: 50 C.,to' C., and coolingthe reaction mixture to a temperature sufficient to crystallize out pureacetoacetanilid.

9; Process for making acetoacetanilid which comprises "dissolvinganiline in toluene, slowly adding diketene' to the solution whilemaintainin -me reaction mixture to a temperature of about 50 C. to 70C., cooling the reaction mixture to a temperature sufficient tocrystallize out a major portion of the acetoacetanilid and subsequentlyremoving the remainder of the acetoacetanilid' by extraction with anaqueous caustic solution. v

10. Process for making acetoacetanilid which comprises dissolvinganiline in toluene, slowly1 )0 adding diketene to the solution whilemaintainlngythe reaction- .mixture to a temperature of about 50 C. to 70C., progressively cooling the :reaction mixture to a temperature ofabout -5 4 0., whereby a major portion of the acetoacetanilid* isremoved by crystallization, concentrating and cooling the remainingliquor tc-remove further crystalline material, and extracting the lattermaterial with a dilute aqueous sodium hydroxide solution to; removethe-remainder of the acetoacetanilid. g 1

- oEoRGE I-I. LAW.

